Through the Gates of Hell
by Minor Itch
Summary: ODST Mattias has been insubordinate, short sighted, hot tempered, through hell, and on his way there again. How will he cope when thrust into another world, one different from the one he left? There will be no lemons. Kaiden/FemShep. OC will have a platonic (father/daughter) relationship with a certain crew member. Once you get past chp1 it picks up the pace.
1. Chapter 1

**This story is having a rewrite, and Chapter one is posted under "Through the Gates of Hell (Rewrite)"**


	2. Into the Maw

**IM back cause i suck at cliff hangers.**

**Also big shout out to dragonheart967 great review. I will correct this as soon as I can figure out how I can fix it also if you have an account PM me you sent exactly the kind of review i was looking for. Next if you don't know this, I may have made Mattias a little to... unprofessional, so you might see a **_**slight**_ **shift in showing of respect.**

**Also themythick, sorry dude, I already decided while writing this chapter (plus i started before i saw any reviews). Also I don't exactly know what you mean but this will be completely original, thanks for the review hope you understand.**

**alright since shepherd is going to be arriving probably this chapter so some background info:**  
**Commander Jesse Shepard**  
**Spacer: Mother: Captain Hannah Shepard: Currently stationed on the SSV Omaha**  
**Father: Colonel Alan Shepard : KIA at an aid station on Torfan when performing Triage on a booby-trapped marine**

**Current training: advanced combat training as an N7, as well as advanced combat 1st aid, and has minimal biotic capabilities. **

**Combat experience: survivor of Akuze, * note due to the traumatic stress of this event, Shepard has become very protective of squad mates, and has been called a "bleeding heart" by some of her peers**

**well enough of that, thanks to my ADD, that took 15 minutes anyway on to Mattias**  
**mass effect is property of bioware**  
**Mattias nilsons name and appearance belong to Pandemic and or EA**  
**halo belongs to 342 Industries**

* * *

As the Gopher was launched Mattias' cocky attitude quickly began to diminish as the blood rushed to his head he reached up and touched the burnt hair and flesh that ran along his left temple. "SHIT!" he yelled, just short of a scream, as he recalled where a jackal grazed him with a beam rifle after he had taken out a brute with his knife.

_Okay this is bad_, Mattias thought mind racing, _Waaaaaay too many suit breaches, and my armor is basically melted together, hell i can't even move my left wrist let alone take off the armored glove, I'm gonna die. First time for everything._That was all that ran through his head before his brief moment of clairvoyance gone now, before his cocky attitude returned and he quickly keyed the comm as he reached the last 30 seconds until contact.  
"IN WORDS OF MY GENERATION, UP. YOURS!"

Back on the _Sparta_, Captain Cooper grabbed his nose at the sound of what was likely going to be Mattias' last words ever ,thinking of his sheer stupidity.

"Sir, the enemy ship is preparing a short range slipspace jump" one of the crewman reported.  
_Great this is just beautiful, just lost the toughest orneriest jarhead I've ever met. Sad thing is, I think I'll miss him breaking the doc's nose every time he see's him._

* * *

Mattias just watched as his pod got within 200 meters his target, his pod's warning alarm started going off. _Shit. Slipspace jump, looks like my CO was right, I am one unlucky SOB._

* * *

_Location- Peak 15, Noveria_  
_Year- 2183 A.D._

The tension was thick in the tram heading back to Peak 15's entrance. on one side sat Commander Jesse Shepard, next to her Tali'Zorah nar Rayya, looking at the floor, fidgeting with her hands nervously, trying to figure out something to say. Across from them sat Liara T'Soni, with her elbows on her knees quietly sobbing into her hands.

"Hey, Liara?" Shepard gently whispered to her friend, trying to bring her some comfort.

"Yes?" Liara replied, followed by a soft sniffle.

"If you need to talk," Shepard softly spoke, "We're here for you."

"Thank you, Shepard, that means a lot to me" Liara replied, starting to regain her composure just a bit.

After a few moments more of slightly less awkward silence the tram began to come to a halt, and the team began to make it's way out of the complex.

Shepard was about to open the door leading out when she saw something big on the edge of her radar, " Team hold position"

"What is it Commander?" Tali spoke first.

"There's something _big_, outside," Shepard answered," Remember that colossus we took down?"

"Yes..." replied the young quarian girl.

"Do you Remember how easy it went down?" Shepard continued.

"Keelah! You don't mean..."

"I do, but I have an idea," Shepard continued, " What I want you to do is hack into its sensors, try to trick it into ignoring us."

"Alright I'll try," Tali said, her luminescent eyes beginning to glow with determination, " We'll have between 5 to 10 seconds.

* * *

_Location: In decaying orbit over Noveria_

"SHIT!" that was all Mattias could say as he slowly began to regain his sight. _Okay so either that Concussion I have is REALLY bad, or I just did a slipspace jump in a drop pod. Considering I'm over Hoth, I'm gonna' say I've lost a lot blood._

* * *

So far the plan had gone smoothly. The second they had an opening Shepard and team went through the door and quickly found cover. That was all that went right however. the plan was soon complicated by the fact that along with the Colossus there were half a dozen geth troopers along with a geth destroyer.

"_Normandy to Shepard," _Joker's voice filled Jesse's helmet as she downed 3 geth troopers with a grenade, " If you're still walking around down there, just so you know, something just appeared on the sensors. Heading for your position, you might want to get moving. Unless you like being a pile of red snow?"

"Joker Come in!" Jesse shouted, but getting only static. she knew it was pointless to try again. However, when she saw the streak of red sticking out against the white sky, she realized what Joker had told her, " TALI! LIARA! INCOMING!"

* * *

Mattias couldn't help but start singing the song Screaming Eagles (by Sabaton look it up) as he guided his pod down to the surface, taking a special note on the squad of troopers engaging what looked like a Scarab. _Well time to make an entrance!_ With that one thought, he began to program targeting computer to hit the mini Scarab right in the center of mass.

* * *

Jesse stood dumbstruck at what she saw. What appeared to be a missile had suddenly changed course and was flying with an increasingly erratic flight path, until it smoothed out and impacted with the colossus, knocking it on it's side, crushing the geth destroyer. The 'missile' had embedded itself about half way into the walking tank, and appeared to be about 2/3 the size of the mako.

"Tali! What is that _THING?" _Jesse yelled, curiosity in her voice.

" I don't know Shepard," Tali responded as she ducked back into cover, checking her omnitool, "Scans show 1 Life form...Shepard it's human! Vitals show he's going into Cardiac Arrest!"

Hearing the words, Jesse's mind began to race. _Hopefully I can stabilize him, but how do I get him out of there, let alone off that colossus?_

Her thoughts were interrupted by a loud roar from the pod. When she peeked out of cover she noticed thrusters engaging on the pod, accompanied by loud hissing sound indicative of a thermite charge.

* * *

Mattias just smiled at the pain that filled his body at impact, jarring him back into consciousness. _Huh. So that's what death feels like._

Suddenly he was brought back to reality by the sudden moving of the mini scarab as it began to stand back up

"SUCK ON THIS YOU JÄVEL!"

* * *

Never had Jesse Shepard been so shocked. Those words came from a VERY angry and badly injured man. She watched as the pod burrowed through the colossus and impacted hard into the ground.

The pod had a gold tinted windscreen, covered in streaks of soot from atmospheric reentry,and had a decal of a flaming skull with the silhouette of another pod in the background, with a ribbon below it that said "FEET FIRST".

As the geth opened fire on the pod, Jesse was shaken out of her trance. _No he's as good as dead if we don't do something! Come on, do something!_

* * *

As Mattias cleared his head, his body automatically started to prepare. _Well i've survived this long, I'm not going down to some fancy covy robots_.

As he finished chambering a round in his MA5C, he began to notice a crack forming on his canopy. _Well I was getting bored in here anyway_. he thought as he reached for the release handle.

* * *

"SUPPRESSING FIRE!" Shepard finally ordered, "Tali, use overlo-"  
_**BANG**_

At the sound of the bang, Shepard watched the hatch of the pod blow off and take out the trooper right in front of it knocking it into the cliff side.

_NO! They killed him!_ That thought repeated seemingly a million times in her head, just repeating until she saw the strobe of an assault rifle accompanied by it's angry roar, downing the first geth.

What Shepard saw next terrified her. She watched as a figure stepped out of the pod, covered in armor that had a jagged hole in the center of chest showing the exposed bone and charred flesh beneath, along with a piece what looked like rebar in his left shoulder with another one in his left calf. The helmet had a black tinted visor, but was missing a large triangle shaped fragment that left his right eye visible, and part of his nose, on the left side there was long gouge on his helmet. What worried Shepard the most was the 2 parallel lacerations that were starting to bleed through what looked like a yellowish foam inside the wound. on top of all this were the many dents and burn marks all over his body.

"TODAY IS A GOOD DAY FOR YOU TO DIE!" yelled the unholy figure full of rage, pulling the length of metal in his calve out and tackled it to the ground shoving the spike into it's optic

* * *

**there chapter 2 out, now I really like writing the stuff with Mattias in it but hate doing Dialog for canon characters so**  
**for any good authors or group of authors like the one's doing the IronManXMassEffect Crossover would like to PM me about changes or for beta reading let me know.  
**

**Please let me know your opinion in a review**


	3. And so it Begins

**A/N Well I'm back And I'll probably be doing an update every day or two, but they'll be shorter chapter's, about 1500 words or so, atleast at first. Now that I've received a review for chapter 2, I have come to a decision:**

**I will continue updating, unless I get a lot of reviews that tell me to just stop, and as long as I get a review every once in awhile, I'll just assume you guys like it.**

**To random reviewer, who posted **

really ridiculous actions but all considered i love the fic just becasue its awesomely ridiculous cant wait for the next chapter

**thank you, that's what I was going for. I was almost done with this chapter, and I thought you should get a shout out, and if you like it so far, wait until we get to the part where Mattias enters mass effect 2,**

**now shout out to **kingslops **for the first review on chapter two, your review tells me that I'm doing something right so I'll do what I've been doing.**

**Now if anyone would like to see certain encounters between Mattias and other characters, feel free to leave it in a review, don't worry this story will make it to mass effect 2 at the least.**

_THE NAME WILL BE CHANGING FROM "RETREAT HELL" TO "Through the Gates of Hell" within a day of this chapter's release._

**mass effect belongs to bioware**

**halo belongs to 343 industries**

**Mercs belongs to EA**

**One horizontal line = change in perspective**

**2 horizontal lines= small time change  
**

* * *

"Commander, what should we do?" Tali spoke first.

"Tali, contact the _Normandy_, and get Dr. Chalkwas on standby, " Shepard finally spoke, her trance finally broken from staring at the enraged human in front of her

"Yes Shepard," replied the quarian girl. beginning to tap something on her omnitool.

"Liara, stay back, be ready to use stasis if this turns bad," with those words Shepard began to walk towards the now standing man.

* * *

Mattias was standing over his latest victim breathing heavily. The spike that was his weapon still sticking out of the optic of the unfamiliar drone's optic. _Well that was fun to bad it fucking COLD._

Mattias suddenly clutched his chest, pain breaking through the haze of adrenaline, and intensified with his breathing. _Shit, Bastard hear must have nicked my lung through the hole in my armor._

As Mattias pulled his hand away and stared at the steaming blood in his hand, vision beginning to fade.

"Sir, I'm Commander Shepard, are you alright?" Mattias' vision snapped back as soon as he heard the soft voice in front of him._ At least I'm not dead, that is NOT the devil's voice._

* * *

The figure in front of Shepard looked up from his now shaking hand and stared at her, gasping. "Sir, can you hear me?"

Mattias could see the woman in front of him beginning to move closer. _Come on mouth, say something_.

The figure in front of Shepard took a shambling step towards her, then collapsed to the ground_._

"Liara! Stasis NOW!" Shepard ordered, using her own biotics as well, in an attempt to stabilize the now bloody figure before her.

"Shepard," Tali finally spoke,"Doctor Chalkwas will be in the cargo bay along with Kaiden and Ashley!"

"Good work, Tali," responded Shepard, not even looking as she said so,"Keep an eye on our new friends vitals."

* * *

**skipping the part of how they load him into the Normandy's cargo bay because of obvious reasons**

As Kaiden Alenko and Ashley Williams put down wounded soldier on the ground next to Dr. Chalkwas, Ashley stepped back to let the doctor have room.

By now the entire ground team had begun to gather around their new guest. Everyone, save Wrex with concern for his health.

"Kaiden he's having a pulmonary hemorrhage, hold down his shoulders," ordered the doctor with complete calm, "Tali, get over here and monitor his vitals."

With those words, the doctor began to work in silence, the first thing she did was grab a syringe of adrenaline mixed with morphine and injected it into the figure in front of her. _That should keep him out of shock._

After that she put a syringe filled with medigel and injected it into the blood filled lung. The doctor then grabbed an artificial blood IV and put into the charred flesh that was exposed through the melted armor on his right forearm.

Next she grabbed a long needle and attached it to a length of surgical tubing that had a hand pump on it, and inserted it into the lung. She then began to use the pump to remove the displaced blood.

"Doctor!" Tali shouted, "His pulse is _gone"_

"Use overload on him," replied the gray haired women without hesitating, "It should restart the heart!"

* * *

Mattias was going through hell, his body proving to be weaker than his will to live. _Well, looks like this is it, who knew I'd die from a lucky shot from a flashlight,_ He thought, content to let the darkness around him to finally sweep in.

* * *

Shepard just watched as the doctor worked, every move made with practiced precision. Shepard was surprised at quick decision to use an overload like a defibrillator.

"CLEAR!" shouted the quarian pushing a button on her omnitool, sending an arc of electricity through the limp form before them.

"PuuuUUH," gasped the formerly lifeless figure, eyes snapping open, which immediately locked onto a now blood spattered Kaiden still holding his shoulders down, leaning over him.

* * *

Mattias snapped awake to see the blurry figure, somewhat resembling the doctor from the _Sparta._ Blood immediately rushed through his veins, the pain somewhat dulled, but supplemented with rage.

"Jag ska spöa dig!" shouted the figure laying on the hull, and without missing a beat, punched Kaiden square in the face with a sickening crack, which simultaneously ripped the IV out of his arm.

"What the hell man?" Kaiden yelled clutching nose.

"Kaiden, are you alright?" Shepard said with conflicting emotions of concern and worry.

"I'll be fine Shepard" replied Kaiden, blood beginning to run through his fingers.

* * *

Mattias realized that the man he had punched was not the man he thought it was. He realized it when he didn't get suckerpunched in return._ Something isn't right._

As he began to stand up, the ringing in his ears began to dissipate as his hearing returned to him.

"For a guy who just died, you sure can throw a punch." said the voice that he heard before he passed out, this time the voice sounding slightly agitated, but still filled with concern.

* * *

Shepard noted the steely eyes that had been so filled with rage settled on her, flickering with recognition. "We're your friends, Not Your enemies."

At the sound of her voice, she noted that once again those eyes filled with recognition. instead of returning to rage, they filled with loss. As he took a step towards her, he grabbed the spike in his upper torso, slowly pulling it out with a pained grunt.

"Natalia?" was all he said before he lost consciousness being caught by Kaiden with his biotics, hand still on the spike in his chest, empty syringe in his neck.

"Doctor," Shepard said after they moved him onto a gurney and headed for the elevator, "When did you sedate him?"

The doctor glanced up from her omni tool, "About the same time he broke the Lieutenant's nose, it should have knocked him out before he stood up."

"Interesting," Shepard responded, before the elevator door closed._ That guy should have been in a morgue, not falling from orbit._

"Garrus," Shepard said turning to the turian repairing the mako

"Need something?"

"Yeah," She responded, " See if you can get that pod in here with the Mako's loading crane."

"I'm on it."

It was then that Shepard saw the damaged helmet, noticing the words _The 4th Norseman_ painted along the top edge of the visor. Turning the helmet over, she saw the blood, human and otherwise, that dotted the interior. That's when she noticed what looked like an old usb port along the bottom edge.

"Hey Ashley," Shepard said to the women on the workbench next to her. "want to learn more about our newest nutcase?"

"Hell yeah," replied the gung ho marine, "At least then we'll know why he likes to break noses"

After a few minutes of trial and error, along with with a few snide comments about it smelling like burnt electronics and flesh, courtesy of Ashley, they managed to set up a crude link between the helmet and the computer on the workbench.

"All right, I hope you brought popcorn," Shepard said, pressing play.

The video began by showing showing what looked like a squad in the same armor as their guest, rushing down the hall on a space station

* * *

_**I'm going to write this from Mattias' view, this will be a flashback type thing**_  
Mattias and his squad had just put their armor on, and were on their way out of the armory. The window that ran the length of the room giving a view of earth , with a view of several covenant ships that had made it through the defence grid.

"Shit sarge, is it true?" Came the voice of their newest squadmate, Shiner

"well considering I told you we were under attack, and the rather large explosion, I'm just gonna hafta say," Mattias responded, very annoyed,"YES DUMBASS! Now, Rico, Mikey, you're on point. Jethro, change Shiner's diaper. Lt. Dunn needs us at the atrium, his squad's pinned down by sniper and they're being suppressed by 4 brutes, each leading a squad of grunts. Double Time it!"

As his squad moved down the hall, they stacked up on the opened door to the atrium. Closest to the door was Rico, then Mikey, both holding M7S's( silenced smg). Then Mattias, holding an assault rifle, followed by Shiner, holding an M7S smg. Farthest from the door was Jethro, their medics and marksman, holding a battle rifle.

"GO!" was all Mattias said, and they quickly entered, each one giving suppressing fire as they rounded the corner, heading to the toppled pillar that several ODST's were hiding behind

"Lieutenant," Mattias said once he was crouching behind a knocked down pillar, "Echo squad awaiting orders."

"Sergeant," Dunn said, putting a fresh clip in smg, " What's left of Alpha and Bravo are in bad shape. You and Delta need to hold this position while we move the wounded back to the infirmary."

"Sir, what about Natalia?" Mattias asked, standing back up to empty his clip into a brute , perforating its skull

"Mattias," Dunn said, tossing a grenade into a group of grunts, " I sent Bravo through the rec area to to try hit them from behind, Corporal Jenner was dragged back with a shattered femur, Jenner said that she they got separated when Covvey reinforcements showed showed up, said he heard her screaming. I'm sorry."

Mattias went silent, unable to handle this bit of news. "Sir, permission to advance."

"Permission denied, I need your bastards here you'll just lose another man."

"SHIT GET IT OFF!" Shiner , who had been returning fire, had suddenly took an overcharged plasma burst to the helmet.

Without a second thought Mattias hooked his arm around Shiner's neck, pulling him to the ground and quickly removed the helmet before the plasma began to eat away at the inside. He then took the now half melted helmet and shoved it back on Shiner's head.

"Next time you take a plasma hit to the helmet you're on your own!"Mattias shouted inches from the now partly helmeted ODST. Mattias then punched the young soldier in the stomach. "Now stay down, you've done enough Shiner."

Mattias then stood up to kill the grunt that had hit shiner, when flash of light zipped into the edge of his helmet, gouging long hole through the side of his helmet. Mattias ducked back down, avoiding the follow up shot. After touching the newly exposed and cooked flesh, he turned back to the lieutenant, "Sir, my _squad_ will hold position as ordered!"

Mattias then grabbed shiner's smg and put it on his back. "Jethro take out the sniper, Mikey, Rico, you're on grunt duty. On my mark" Mattias double checked his ammo counter. "MARK!"

The moment those words were uttered, all four soldiers popped up taking out their assigned targets, Mattias finishing off the Brute Shiner had wounded. He then took a spike to his shoulder which had knocked him onto the ground. Jethro, however having taken his target out, finished off the other brute.

"Alright boys, hold this position!" Mattias ordered sliding another magazine into his pistol, then reloading his rifle, "Shiner, grab a helmet from the wounded."

"Y-yes sir!"

"Jethro, Biofoam, 2 cans. You're in charge"

"Sir, don't leave Nat behind," Jethro responded, putting the two cans on Mattias' equipment pack.

" I won't "

Turning to Mikey, he tossed Shiner's smg, who promptly caught it. "Mikey, teach Shiner what end to point at the Covenant."

"I'll try, but no promises."

"Rico, If I die, kick my ass."

"Gladly, sir!"

"Lieutenant, I am going to recon Bravo's last position, and will recover any survivors _SIR."_ Without waiting for an acknowledgment, Mattias quickly headed to down the hallway the Covenant had come through.

* * *

As the video turned to static, Shepard stood there dumbstruck._ So that's his name, Mattias._

"Hey, Shepard?"

"Yeah, Ash?"

"That planet in the background, I think it was earth." Ashley deadpanned, pale faced.

" Yeah..." Shepard responded, still digesting what she had just seen. " Come on. I want to get a good look at him before he wakes up."

"Aye aye, ma'am."

* * *

Walking into the Normandy's medbay, the two women weren't greeted by a welcome sight. On the far end of the room , Mattias was laying on a operating table, the armor that had once been on his upper torso lay on another. Evidently it had been cut off by plasma cutter, given the matching jagged line on both the armor and down Mattias' sides.

"Hey LT," Ash said, giving a whistle, " Even with half his muscle burned off, he's more ripped than you."

"Uh huh," replied Kaiden, leaning over Mattias, waiting for him to wake up, nose now popped back in place, cotton ball in each nostril. "Why do you think his wrists are restrained. Besides, I want to see the look on his face when he wakes up."

"Dr. Chalkwas," Shepard said, ignoring the back and forth between her two friends, " How long until he wakes up?"

" Should be any moment now," the doctor replied, preparing for the surgery that would follow. "The pulse rounds that nicked his lung have logged into the back of his armor, so all I have to do is apply a local anesthetic and remove that spike in his shoulder." On cue, Mattias eyes snapped open, instantly locking on to Kaiden.

* * *

_Not you again_, Mattias thought, readying his arm to strike, only to strain against the shackles now on him.

"Not so tough now are you?" asked the familiar silhouette above him, leaning in so he was about six inches above his face.

Mattias responded with a headbutt that resulted in a satisfying crack.

"Son of a!" shouted the figure, sending a punch back, which Mattias dodged by cocking his head to the side, followed by another headbutt.

* * *

Ashley, who had set her omni tool to record, watched kaiden walk over to the first aid station by the door. Now she was struggling to hold in her laughter. _Joker's gonna love this!_

Doctor Chalkwas , who until now had been silent, now spoke: "Young man, you don't realize the extent of your injuries do you?"

Chalkwas turned around to ready her tools. As she grabbed a container of medi gel, The room filled with the sound of a wet _pop_, Ashley then saw Mattias slip out of the wrist restraint, then undid the other.

Everyone stared as they watched Mattias swung his legs around and stood up.

* * *

Mattias stood up, grimacing as he popped his dislocated thumb back in place.

"Ma'am, I've suffered a bayonet wound from a Spiker, both perforating my solar plexus, and lacerating my small intestine, successfully stabilized with bio foam." Mattias stated casually, then continued, "I've also received 4th and 5th degree burns to both the upper torso and and my right forearm, both requiring extensive skin and muscle grafts." Mattias paused for a breath, then went on "I also have minor shrapnel throughout my body, no treatment necessary. Not to mention the 2nd degree burns that are all over my body. Not to mention a nasty concussion."

When Mattias had finished, he noticed the shocked looks on everyone, except for the gray haired women in sterile scrubs. _Something is not right here._

" And yet here you are," the women began, "In _My _medbay, in a state most are only found **dead**, adding to my work load," she said nodding to the man putting a salve on his nose.

"Ma'am, considering I'm not in shock," replied Mattias, " I'd say I'm walking wounded. Ask Corporal Bennette if you disagree."

"Well there's no Corporal Bennette on this ship," the women replied back before turning to the younger red haired woman behind her, " Commander, can you do something about this? I doubt the Lieutenant here will be able to assist without further injury to himself"

_Shit, I just broke a superior officer's nose. Repeatedly._ Mattias thought, before coming to attention, snapping a crisp salute.

* * *

Shepard was analyzing the figure before her, arm still raised. _Interesting,_ she noted, _He respects rank, but from his helmet's video, he must value this 'Natalia' more, I'll have to figure out who this is._

"At ease," Shepard said after about a minute, his face giving just a glimmer of pain while moving to parade rest._ That spike must be in the muscle. _"Sergeant, what was the last order you received from an officer before engaging enemy forces planetside?"

"Ma'am, to Deploy via Gopher to an unknown Covenant ship and provide support to Sierra 1-1-7," Mattias stated, staring into the distance, "However, the ship engaged an in system slipspace jump, however my pod was inside it's envelope, sending me into a textbook orbital drop. Ma'am"

"Who was it who issued you this order?" Shepard continued

"Fleet Admiral Hood. Relayed through Captain Cooper, commander of the _Sparta_ orbital defence platform."

"What's the current date?"

"November 3rd 2552," stated Mattias,

"Sergeant, are you aware that the _current_ year is 2183?" Shepard replied, holding back her shock, unlike Kaiden and Dr. Chalkwas, their eyes widening. Mattias however, relaxed, going from ramrod straight, to leaning against the bed behind him.

"Well shit, ma'am," Mattias began, "I could use an explanation, like why there were friendly aliens around me when I punched your lieutenant" Mattias was now staring at Kaiden, who just seemed to shrink into himself."

"What was it you said about Slipspace?" Kaiden now spoke, still holding a tissued over his nose.

"All I can tell you is that it's the UNSC's method of FTL," Mattias answered, "Works by ripping into another dimension, then spits you out after awhile. Hell, That's probably what happened, it just spat me out in the wrong place."

"What are you saying?" Ashley asked, somewhat accusingly.

"What I'm trying to say," Mattias replied, " Is that instead of going to oblivion, I was spit out in the wrong universe."

Now it was Shepards turn to ask a question. "So you're telling us that you're from another dimension?"

"Yup, Master Gunnery Sergeant Mattias Nilson, ODST and interdimensional puke," Mattias humorously deadpanned, earning a snicker from Ashley and an amused smile from Dr. Chalkwas.

"I'm Commander Jesse Shepard" Shepard began, gesturing to each crewmember respectively, "That's Gunnery Chief Ashley Williams, Lieutenant Kaiden Alenko, and this is Dr. Chalkwas," she finished, offering her hand, "Welcome aboard."

Mattias then responded with a pained grunt as he pulled the spike out of his shoulder and jammed the bloody end in into the bed he was leaning on. He then took her hand "Ah, what the hell."

* * *

Mattias turned to the doctor after Shepard left. "Alright Doc what you got for me?"

"Well Master Gunnery Sergeant," she began, "Would you care to tell me how you're still breathing?"

"What do you mean Doc?"Mattias somewhat coyly responded, "Surprised I have a mechanical lung?"

* * *

**A/N: a cliff hanger, because I got tired of typing, yes this is a really long chapter(relativley) but now since I got the merge done, It should be much easier to follow the story.**

**Now I will give a quick description of Mattias:**

**He looks like Mattias Nilson from Mercenaries 1: playground of destruction property of EA, but with a goatee. He's 6"6" and built like Vin Diesel. **

**Okay well probably another update by saturday.**

**please leave a review, don't forget to use a label so I can address your concern.**


	4. Chp 4 Respect

**A/N: HEllO BOYS, I'M BAAACK. Sorry, I had to finish that independance day quote from chapter 1, now I want to find a way to bring Jethro into the story, mainly because I feel that Mattias needs a foil, or an opposite to balance out the destructiveness that is Mattias.**

**Also, forgot to put this in the end of chapter 3 A/N: Jag ska spöa dig is swedish for"I'm going to kick your ass"**

**Now, I'm going to set up a poll on my profile once I start receiving enough reviews.**

**As of now I have received a total of over 600 views, cool. Now I could use some intresting one-liners for Mattias, preferably not all from red vs blue, please leave these in a review, or pm me if you want to see them possibly used.**

**Now for obvious reasons, Mattias will be sitting out for a awhile before accompanying Shepard(who will be referred to as Jesse from now on, probably). Don't worry this is the time that will be used to accomplish all of the VERY annoying side missions of mass effect 1, and face it if you do all the side missions or even most of them, your playthrough will be about 45 hours, as opposed to just 11 hours of just doing story missions, That's how much I played Mass Effect, and that was literally BEFORE it was cool. So much so, that I don't even have to refer to my current cmdr shepard,(named Dimitri) for this, but I will, to appease the haters who have only played ME2 and 3.**  
**don't worry I will still refer to the codex and halo wiki whenever I have to compare/Contrast etc. when appropriate.**

**be prepared for our favorite noob, the one that lives up to his namesake, to be alive, just for several scenes I want to use him in.**

**Mass effect belongs to BioWare**  
**Halo belongs to 343 Industries**  
**Mercenaries belongs To EA, ( you know, before they killed it by cancelling the third game, mercs inc, and fired most of pandemic's staff)**

**Now we return to our hero, scene already in progress.**

_FYI: Mattias is still wearing his arm, shoulder, and leg armor, which is for the most part, he's still stuck in.)_  
"Yes, " Dr. Chalkwas began, " In fact I am."

"Well," Mattias began, no longer smiling, "Let's just say I've been in some classified operations, had some stuff done to me, and for some reason, that stuff made my body reject the transplant, so they put this thing in me."

"Hmm, I see," Chalkwas replied, typing some notes in her omnitool. "Now would you please allow me to apply some medigel to your wounds."

"Sure why not." Mattias responded, swinging back onto the table. "Care to tell me what it is first? cause it's going to take more than just a bucket of aloe vera for these burns."

As the doctor described the substance, she applied some to his still bleeding shoulder, and to his amazement, it slowly closed the wound, not even leaving a scar.

"Let me guess," Mattias began, "I get to take a bath in sci-fi vaseline?"

"Sadly no," She answered, " We'll have to remove the dead tissue."

"Sweet" Mattias again smirking, "Bring on the maggots!"

(A/N: Maggots will only eat dead/rotten flesh)

"While I admire your enthusiasm," Chalkwas joked back, "We'll be using a surgical laser. Then we can begin an artificial bone graft, followed by several applications of medigel a _day_ for several weeks."

"Right," Mattias said, no longer light-hearted, "So combat ready in three days."

"If you want massive internal bleeding and cardiac arrest, yes," the doctor said matter-of-factly, "Or we could try stop at the citadel, give you massive surgery, and back up to speed in _4_ days, but only if you follow a physical therapy regimen,"

"I'm gonna say that second option sounds pretty good right about now," Mattias finally said, choosing to forget the second part of the second option.

"Good. First put this in your ear," she said, holding out an ear piece, " This should allow you to understand the nonhuman crew members. Now fortunately for you, I already took some scans for my file. You're free to go sergeant."

Hearing those words, put the earpiece in, which quickly formed to the ear. He grabbed the piece of torso armor off the table, then the bloody spike, and started to move towards the door. _Good, now maybe I can repair my armor. Of Course, after I find a way out of it._

Jenkins stood with his back facing the medbay, somewhat bored. _Man, why does the Commander have me here for a man that's probably going to die?_

Just then, he heard the door hiss open behind him. Turning, he saw what looked like everything you don't want to live through.

As the crewman standing guard at the med-bay door turned around, Mattias noted the corporal chevrons stitched onto his fatigues.

"What are you staring at _Corporal?_" Mattias accused the baby faced soldier, who was staring at his still charred and cracked flesh of his torso, " Never seen plasma burns before? They're very painful.. Now. Step. Aside."

"S-sir!," He replied, visibly shaking, " C-Commander Shepard wanted to see you. When you were finished in the med-bay."

"When I was finished in the med-bay..." Mattias was now glaring at the corporal.

"SIR!" Jenkins managed to squeak out, gulping.

"Now, drop and gimme 20!" Mattias shouted, inches from the terrified kid in front of him.

Jenkins dropped to the floor not bothering to wipe the flecks of spittle on his face. But before he could even start his first push up, he felt a hand pick him up roughly by the waistband.

"You wanna know why they call me the 4th Norseman?" questioned the figure now carrying him up the steps.

"Sir! Yes Sir!" Jenkins reflexively answered.

"Because, Death doesn't choose who lives and dies. I do."

_OH GOD! HE'S GONNA KILL ME!_ With that one thought, Jenkins, could barely keep from whimpering.

Once Mattias reached the top of the steps, still carrying the terrified corporal, he turned right and followed the sound of Shepard's voice, coming from behind large door.

"Alright," Jesse said, " Unless we have anymore helpful information on the Conduit, we're done here"

Just as Jesse finished speaking, the door let out a chime, causing everyone to look in it's direction. Standing in the doorway was Mattias, one arm holding the front half of his now useless armor. In the other however, hanging by his belt, was a very frightened Jenkins.

"Ma'am!" Mattias said dropping Jenkins on his face with a thud, coming to attention, "Permission to speak freely?"

Behind her, Jesse heard Wrex give an amused "hmmph"

"Permission granted" She replied, ignoring a giggling Tali.

"Ma'am," Mattias began, " This corporal could use a reminder of proper discipline towards a senior noncom. I was wondering if I would be allowed to remind him?"

"I don't think that will be necessary," Jesse answered, somewhat mortified by what kind of reminder Mattias meant. Turning to Jenkins, she continued, "Will it?"

"N-n-no Ma'am" Jenkins responded, trembling.

"Good," Jesse said, slightly amused, "Now, Everyone but Garrus and Sergeant Nilson are dismissed."

"Now," she said once everybody else had left, "Master Gunnery Sergeant Mattias Nilson, This Here is Garrus Vakarian, He's a turian."

"Call me Gunny," Mattias said, offering his hand.

"Now," Jesse said, once introductions were finished, "Garrus recovered the pod you arrived in. Garrus?"

"It's like the Commander said," Garrus began, flaring his mandibles as he talked, "However, it seems that everything is code locked. So we can't do anything other than look at it for now."

"Good, that means you haven't messed with some of my stuff," Mattias said, earning a look of skepticism from the other two, "It's code locked to my neural interface."

"Well Gunny," Jesse said beginning to get agitated, "Would you care explain what that means?"

"Well," Mattias began, "To put it simply, I have an implant in my skull. One of it's many uses is as an IFF, which is a fail-safe so that a non-combatant can't use the drop pod. So bluntly put, I'm the only one here that can make her put out."

"Well then," Shepard said, turning to the chuckling turian next to her, "Why don't you take our friend down to the cargo bay. I'm sure he'll want to take a look."

"Sure thing"

"Hey Shepard," Mattias said before turning to follow the turian, "Doc said something about the citadel and surgery. Also, we might need 20 pounds or so of maggots."

**A/N I've switched to using a line of s, mainly to make it easier for uploads. Now I'm not sure of how to do this, would you like me to do an update as soon as possible, with lengths like this, or longer, with possibly more refinement and ridiculousness?**

**Well, how do you like Jenkins living, this is mostly just so I can have someone who will be utterly afraid of Mattias, and still be forced to interact with him. **

**Now if this was amusing, listen the song Suicide bomber, by Tripod, **  
**well that's about it. Please leave a Review, and thanks for reading.**


	5. First Impressions

**A/N: Well I'm back. I'm going to try and keep these short from now on. First though to respond to themythick:Perhaps...Perhaps...**

**FYI For those who want to see more of Echo Squad, Visit the Poll on my profile for details.**  
**also if any characters from mass effect are OoC, let me know, and give me tips if you got 'em**

**Mass effect belongs to bioware**  
**Halo belongs to 343 industries**  
**Mercenaries belongs to EA**

**Now the story:**

"So Garrus," Mattias began as the elevator doors to the hanger closed, "How easy would you say it is to work a blade through turian hide?"

"Uh.." Garrus replied with a nervous tone. "Why?"

"No reason," Mattias nonchalantly answered as the elevator eased to a stop, "Just trying to make conversation"

When the elevator doors opened Mattias was not greeted by a welcoming sight. Before him he saw what resembled a humpbacked frog trying to pry open a container on his Gopher. Next to him he saw a young hooded woman with a glowing glove.

"Wrex, What are you doing?" As Mattias heard the woman's familiar accent and voice, he felt the life drain out of his eyes, adrenalin beginning to quickly flow through his veins.

"Komma ifrån henne!" He shouted, pulling a boot knife that ran half-way up his shin, and in one move gripped the blade, bringing it up past his shoulder.

As Garrus heard the shout from Mattias, he saw him reach for a boot knife, going into a throwing stance. Reacting quickly, he grabbed his wrist, preventing him from throwing.

"Sergeant, What are you Doing?" Garrus question was quickly answered with an elbow to the jaw. As the turian clutched his now dislocated mandible, an an arm quickly struck his left shoulder, dislocating it. without stopping, Mattias tackled him to the ground, one knee on his neck, ready to snap it, his left hand holding the knife over his heart.

Hmph, I like this human, he's got a krogan in him"

Mattias was heavily breathing, the adrenaline haze slowly ebbing away. _Shit! wheres Nat?_  
He then snapped out of it when he heard the amused voice behind him.

"Oops," Mattias said, standing up, offering to help Garrus up, " You ever hear of PTSD?"

"Don't worry about it," Garrus slurred, begrudgingly, "Just don't carry any knives when you're not fighting,"

"Garrus!" Shouted the woman, this time Mattias flinched, but resisted the urge to kill the krogan, "Are you okay?"

"Don't worry Tali," Garrus said, popping his mandible back in place so he could speak properly, "I'll live"

"And you!" Tali said, turning towards Mattias, who was beginning to feel overwhelmed, "What was that about? Do you hate non humans?

"Natalia," Mattias whispered, letting his grip on his emotions begin to fall, tears beginning to form. blinking them away, he regained control, "No. Not _my_ Natalia."

"I'm sorry but my name's Tali," She answered, anger turning to confusion.

"Yeah," Mattias answered quickly trying to change the topic, "My name's Mattias. Now May I take a look at my pod?"

Having received a nod of approval from Tali, he moved around her. When he approached the pod, he placed his hand on a panel inside the pod. Five seconds later, a heavy duty hatch lowered down on the back of the pod.

"Now Ladies," Mattias said smiling again, closing the hatch after seeing its contents, "I have a date with some maggots and a doctor on this 'Citadel' place. If anyone of you try to touch the contents of this pod, I get a coat." Then he looked in Garrus' direction, "And You look like you'd make a nice trenchcoat."

With those words, Mattias grabbed his helmet off the table next to a row of lockers tucking it under his arm, and went back up to the elevator.

Ashley was beginning to tire of how slow the elevator was. As she waited, her thoughts began to turn to the newest addition to the crew.

"You're drooling on yourself,"

Ashley quickly snapped open her eyes, blushing like a cherry, eye's widening when she realized who had said it.

Mattias smirked at her sliding on the almost useless helmet back on his head, watching her quickly wipe the corner of her mouth. "I must look really good for an old burnt bastard."

"That's not what I was thinking about, _Sergeant_." She responded agitated.

"Excuse me," Mattias retorted with a chuckle, "Pulling rank doesn't work like that. Your a navy Chief petty officer. I'm a Master Gunnery Sergeant. The equivalent of a Master Chief Petty officer. But I'll ignore the insubordination. For now. Now are you do you want to take me to the Commander, or do you want to make sure the turian thing didn't piss himself all over the deck?"

"Fine Udina, We'll take Mattias to your office. _After_ we go to the Med Clinic." Jesse said, begining to lose her self control.

"Not good enough Shepard, I want to be there when you arrive on the Citadel. This 'ODST' could be bad for us, the council will just use it t-" Jesse closed the comm channel, beginning to get a headache from dealing with Udina. As she turned to leave the Comm room, The door eased open with a blushing Ashley leading a smiling Mattias.

"Commander Shepard, " Mattias began, saluting, "Permission to speak freely?"

"Go ahead," Jesse said, feeling her headache beginning to get worse.

"I think Garrus wet himself," Mattias said, seemingly ashamed about something, "Also I may have dislocated his shoulder."

"And why did you do that?" Jesse said noticing the reaction on Ashley's face.

"I'd rather not say," Mattias answered, "You may or may not trust me, I don't trust any of you."

"Well I hope that changes," Jesse finished turning to Ashley, "Ashley, take our guest to meet Joker, we're 5 minutes out from the Citadel."

"Yes, Ma'am," Ashley said snapping a salute.

"Hey Ash Got that video you took of our newest 'pet'." Joker began when he heard the foot steps behind him, " Gotta say, for goin' through a deep fryer, he can throw a punch, Can't wait to see what he does to Garrus with the pole up ass."

"You don't have to." Mattias said in a flat tone, making the pilot jump.

"Aw hell dude," Joker said getting his first up close look at Mattias, " You work _Fast_! Any way were about to hit the Citadel."

As he finished speaking he piloted towards the relay. "Annnd, Ta DA!"

Mattias just grunted, "Seen bigger, killed almost as big."

When Mattias received looks of concern from both Ashley and Joker, "What, it's need to know. I don't think you need to know."

Once the Normandy had docked, Shepard, Ashley Both now wearing armor), and Mattias were in the airlock, waiting for the pressure to equalize.

"So Shep," Mattias said breaking the silence, "Any word on the maggots? The charred flesh look kind of itches after a while. Mattias smirked behind his fractured armor, taking pleasure in the look the two women gave him.

Just then the airlock hissed open, showing an impatient looking man. "Udina, I thought I told you that we'd see you _after _we stopped at the clinic." Shepard began, very annoyed.

"And I thought I told you otherwise Commander," Udina replied, already hitting a nerve in Mattias.

"Who are you, I, I'm kind of scared," Mattias interrupted trying to sound as traumatized and helpless as he could, earning a sideways look of disbelief from both Ashley and Shepard.

"Well don't worry, I'm here to help you," Udina replied, tone changing as he closed the distance to Mattias.

As soon as Udina extended his arm towards him, Mattias, grabbed his wrist with his right hand, bringing his left hand to grabbing Udina's bicep just above the elbow. Mattias then snapped the arm 90 degrees the wrong way, dislocating and breaking Udina's elbow in a space of about 3 seconds. Mattias then gave a hard punch to the stomach, knocking him on the ground. He then placed his knee on the politician's neck, pinning him.

"Thanks, I feel much better," Mattias said, pulling a Kabar from his belt, beginning to slowly drag the blade along the bridge of the politician's nose, "By the way, I've been thinking about getting a new leather coat. I'll keep in touch."

Ashley was impressed with how quickly Mattias, had subdued Udina. "Wow, Sarge, hate to see you when your pissed at people who aren't strangers."

"Yeah well, that's how you get busted down from lieutenant to corporal," Mattias said, somewhat nostalgically, "Anyway, enough about me. Let's get to that clinic. Besides, it smells like Mr. Dignified just pissed himself."

As Mattias stood up to leave, Udina, didn't move. Aside from shaking, and whimpering, one would have thought he was dead.

**A/N: Well how's that? Mattias has single handedly done what every body wants to do, but only gets to watch Anderson do,( In ME 1 not 3, where we get to do something completley worth doing, won't say it here for those haven't played it yet.)**  
**Please remember the poll on my profile. Read and review let me know what you liked and didn't like.**


	6. Diplomacyish

**A/N: Okay well I'm back with another update, but first to clarify to themythick: Mattias was just getting the point that he was going to slowly skin Udina alive, in reality, Mattias would probably just take his scalp.**

**The poll is still open, but I no longer will be paying attention to it. I have decided an Idea that will bring my indecision to a comfortable rest, however I will not be able to do this until I get through Mass effect 1. So hopefully i don't forget what the idea was...**

**still could use ideas for more one liners, so unless i get sent them, mattias just gets less psychotic, and more panzy. Just kidding, but he will be less fun when entering combat**

**well for those of you who like to read my rants: "You tolerate me! You really tolerate me!"**

**Mass Effect belongeth to BioWare**

**Halo belongeth to 343 Industries**

**Mercenaries belongs to EA (Unfortunately, YOU TERMINATED A GREAT GAME SERIES)**

**FYI: I won't drop the EA/Mercs thing, they bought pandemic, then laid off most of the staff, then, cancelled their 3rd installment, Mercs Inc, or something like that, sorry for continuing this rant, but hey, that's what the internet's for.**

"So Shepard," Mattias said, climbing into the taxi, "Do all politicians scare this easy?"

"What do you mean 'this easy'?" Ashley said, cutting off Jesse before she could answer, ignoring the glare she was given.

"Well, back where I'm from," Mattias answered, pulling the brute spike out from his pistol holster, twirling it between his fingers, "I think most politicians are probably dead, also this is the first time I've been near one without being in a chain of command. It was kind of liberating. Hope I get to see him again." _EPIC FORESHADOWING..._

"Well, try not to do that unless provoked," Shepard responded, earning a grunt of amusement from Mattias.

"I don't get provoked," Mattias said, Now removing what looked like shards of shattered glass from a wound on his forearm, using the spike to pry it out, "Besides, he seemed to have provoked you, all in all, I think he's had a moment of personal growth."

"And what would that be Mattias?" Shepard asked as the taxi began to land.

"That if your an asshole," Mattias said matter-of-factly as they got out of the taxi, "Another asshole is gonna come along,and he's gonna make you piss your pants. By the way, I'm still mad he got piss on my boots."

"Well Sarge," Ashley said as they went towards the clinic, "Wish I could have lived in your world,"

"No," Mattias answered, foreboding in his voice, "You don't,"

"Why's that?" Ashley questioned as they opened the door.

"You're too soft," Mattias said, walking through the door to the clinic, spotting the doctor, filling out some paperwork on her desk.

"Dr. Michel," Jesse spoke up, gaining the Doctor's attention, "I think you might want to make an appointment."

"Oh! hello Commander, I was just filing..." Dr. Michel's french accent trailed off as she saw the severely burned man covered in what looked like the melted remains of a hardsuit covering only his arms and from the waist down, revealing a grayish charred sternum, with charred flesh covering at least two-thirds of the chest.

"Well Doc, I can explain," Mattias stated as the began to prepare for surgery.

"You can explain after I operate," She said cutting him off, "Right now get on the table and get that armor off."

"Alright, Doc." Mattias said, vaulting over the low wall that separated the waiting room from the rest of the clinic, drawing his knife as he hopped on the table, "Just give me a second,"

Ashley watched mesmerized as Mattias jammed his knife into a seam on his armored bicep that wasn't melted together, prying open the quarter-inch thick titanium/ceramic armor. Once gap was big enough to stick his fingers through, he peeled it back far enough to squeeze his bicep out of, revealing a small trickle of blood from a cut resembling several scars on his arm.

"What," Mattias questioned, repeating the process on the rest his limbs, "You all that surprised? Hell, This is me on a good day."

_He's built like a Greek God!_ Ashley thought, her face going blank, except for the smile starting to form at the corner of her mouth.

"Anyway, Commander, you might want to go see those politicians, Williams' can stay here and 'stand guard'. Incase someone comes here that shouldn't"

Mattias was now laying on the table, enjoying how Ashley turned red, snapping out of her trance. _Good kid,_ Mattias thought, a privacy screen popping up to let him strip, before putting on his gown.

"Hey Ashley," Mattias called out once Jesse had left, "You want me to put the hospital gown on backwards?"

"N-NO! Sergeant!" She yelled, embarrassment clearly filling her voice, "I'd rather you didn't"

"Well," Mattias chuckled, noting how she was subtly peaking around the curtain, "Either stop lookin' at me with your arm computer thing, or come over here and look."

Mattias' chuckle turned to a laugh as he watched her omnitool shut off as she walked out to wait outside the door. "She seemed nice."

"Now sergeant," Dr. Michel said, returning with her omnitool active, "Lay down,"

"Doc, I want a local, so don't put me under," Mattias said, resting his head on a pillow, "Yes I know your probably going to replace my sternum with titanium, but make sure you well may left ribs, on as well. Second, try and save my tatt's,"

As Shepard reached the embassy, she noticed Anderson, sitting on one of the couches in the lobby, chuckling.

"Captain, you're in a good mood,"

"Rightly so, I just Udina trying to hide a yellow stain under a his jacket," Anderson said, smiling, as he began to stand.

"Yeah, courtesy of a new crew member," Jesse informed, smiling, "Threatened to skin him alive,"

"Hmmm, can he behave in front of the council?" Anderson asked, no longer smiling.

"Maybe," Shepard answered, thinking, "But see if we can leave Councilor Sparatus out of it. Otherwise, I think there'll be more than just threats with a knife,"

"Now there's an amusing thought," Anderson chuckled, "I'll try to get Tevos, and Valern there, unofficially,"

"Try not to use Udina," Shepard added, "They might notice his additional stench,"

When The shuttle landed, Ashley removed her helmet, only to be assaulted by the Swedish swear words grunted to the tune of a Celtic song.

"Commander,Captain Anderson," Ashley said, exasperated, "Good thing your here, Mattias convinced Dr. Michel _not_ to put him under, and well... You get the idea,"

"This is one stubborn grunt," Anderson spoke, then gesturing to the a two asari, one of which wearing commando attire, "Chief Williams', This is Councilor Tevos, and her bodyguard,"

"Ma'am," Ashley said, coming to attention, then turning to Shepard, "Commander, good thing you're not here sooner,"

"Why is that?" The Commander said, heading towards the door.

"Because when I checked 20 minutes ago," Ashley said, trying to phrase it right, "Mattias was biting down on a splint, and they were replacing his sternum,"

"And this man _refused_ anesthesia?" Tevos finally spoke, concern ever so slightly filtering into her usually calm and neutral tone.

"Yes Councilor, he said so right as I left the room." Ashley confirmed.

Mattias grunted out again as the doctor touched the electrodes of the surgical welding kit to his titanium ribs, fusing it to the piece of metal that was his new sternum.

"Doc, where'd you learn to weld," Mattias said, noticing the door slide open, not really giving it too much attention, "I mean, you weld like a Combat Engineer, quick and efficient."

"Master Gunnery Sergeant Nilson," Shepard began, gesturing to Anderson, " This is Captain David Anderson. And this is the asari Councilor,"

"Well, Captain," Mattias answered between grunts, "I'd salute you, but I'd rather not disrupt the doctor's welding,"

"There's no need," Anderson chuckled, "You are, after all, not under alliance jurisdiction, from what the Commander has told us."

"Well, I take it you believe me," Mattias said, then pointing his armored glove at the Councilor, "You however, seem a bit more skeptical,"

"That is correct sergeant," Tevos replied, " I would be more willing to believe you, should you let my bodyguard meld with you, only to decide if you're lying or not,"

"Isn't that the thing asari do to breed?" Mattias began, " Because if it is, the answer's no."

"Why?" The Bodyguard now spoke up, " Is it that you hate nonhumans? Is it because you're with Cerberus?"

"Well, aren't we a little insecure?" Mattias said mockingly, then turning to anger "No, for two reasons. One, Just because my wife was torn apart by a swarm of human sized cockroaches, doesn't mean I'm lookin' for a another. Two, I am a senior non-commissioned officer of the UNSC, and a former Commissioned officer. I also have more Combat experience than any one person in this room. And don't give me that thousand-year life span crap."

Mattias looked, no longer in the mood to play nice. All life leaving his eyes, only this time, instead of draining, it left like a light switch flicked off. His focus was on the asari commando, silencing her before she could open her mouth.

"Now, Unless you want to say something productive, like 'We'll take your word on it', I suggest you leave me be, I really don't want to get off this table when my chest is half gone."

Ashley had been dumbstruck at what she heard through the door. Not only had she found out that Mattias was married, but that he was also a widower. _ Maybe this Natalia is a sister._

"Ashley, You got a minute?" Shepard said, the first to come through the clinic door.

"Sure skip," The marine said, shutting off her omnitool, "This about Mattias?"

"Yeah, did you catch what he said, about watching his wife get torn apart?"

"Yeah, I did," Ashley said, a little angry at herself for being glad that Mattias was available, "Where's this going?"

"Now Ashley," Jesse spoke, a twinkle in her eye, "I saw you looking at Mattias' on your omnitool, so don't get all uppity," Jesse smiled noticing the blush on the woman's face, continued, "Now I know you're attracted to him, but I want you to try and get close to him, and try to learn more about him."

"Y-Yes Ma'am!" Ashley almost giggled, receiving the blessing from her CO.

_Meanwhile, ETA 5 Minutes from ARK Portal collapse, aboard Separatist phantom._

"Shit, " Jethro cussed, turning towards the cockpit, "Yo! Split Lip, We need to hit the gas, or we're not gonna make it!"

"Human," The silver armored elite spoke, not turning from the controls, "I may be more accepting than other Sangheili, but do _not_ state the obvious, or I will kill you all right now,"

"Fine," Jethro answered, "Mikey, Rico, Shiner, anyone injured?"

"Just some burns,"

"None,"

"I'll be fine,"

"Good," The impromptu squad leader said, "Everyone, hold on,

**A/N: Yup, this is gonna get a little freaky. Yeah, I'm adding a plot twist, though, I'm not completely sure how I'm gonna introduce Mattias into mass effect 2, but hey, just remember that no matter what I do, we all accepted Commander Shepard dying, Then being brought back to life, AFTER being incinerated on atmospheric re-entry. Really, the only thing that even helps this event, is the fact that Shepard lands on a frozen planet, that prevents the brain from decaying, kind of like a freezer.**

**Remember: Read & Review, The more reviews I get, the sooner I pump these out. yes that is a gross image, THINK ABOUT IT!**


	7. The Plot thickens, Slightly

**A/N: Well, true to my word, started working on this chapter the day after I finished chapter 6, because i got 5 reviews by now, and now, to address reviews,**

**ALSO: Poll on my profile, still open, mainly because I care about my audiences oppinions, let me know please.**

**Green paw: WTF man! This story might seem like it was crack inspired, but it wasn't. I honestly am disturbed enough by my ability to come up with this, let alone that, I don't want to sound mean but, I need to be able to understand what you're trying to ask, also just, ...wow...**

**Scatter Dust: Don't worry, I already know what I'm gonna do with them. In fact I knew where they were gonna show up **_**before**_** I knew how they were gonna get there.**

**well, enough of that, those were the highlights, glad I'm seeing some repeat reviewers, means my writing is doin' good.**

**Mercenaries belongs to EA ( Not even sure if this is necessary, i'm just using a name)**

**Halo belongs to 343 industries, **

**Mass Effect belongs to BioWare**

**FYI: A Mustang officer is (For example) A marine infantry grunt that works his way up to an officer,**

**Codex entry:**

AMTR VI: The AMTR or "Auntie AM-T" to accident prone Vets, is the Accelerated Muscular Tissue Regenerator. It uses a combination of organic 3D printers and complex VI's along with a special mixture of medigel that has stimcells that are cloned from the indicated patients body. This method of accelerated healing. Also for an unknown reason it will also restore previously obtained scars and tattoo's that may have been removed due to injuries such as excessive burns, removed flesh, etc.

**YES I added the last part of this for Mattias' benefit, bite me. (just kidding, it's fanfic, I have an artistic license here.)**

"Anderson," Mattias said after the two asari left, "You seem like a mustang captain,"

"Sergeant," Anderson said, watching the doctor return with a set of scanning equipment, "You're a good judge of character. But I want to know what kind combat experience you're talking about."

"Well," Mattias began, "My first tour in the ODST's had me fighting in a jungle on the planet Arcadia."

"Fighting who?"

"Rebels," the ODST answered, "Hell, still remember hesitating when this 15-year-old girl popped out of a weapons depot they had stashed there. Next thing I know, she's right next to me holding the handle of the knife in my stomach."

"Son," Anderson reassured, "Anyone would have done the same thing, what happened?"

"What do you think, I snapped her neck," Mattias said, earning a look of disdain from the captain, "And no, I don't regret it. If she had been smart, she would have given up, or had driven that knife straight into my heart. It was a justified kill."

"What, no remorse?" Anderson said incredulously.

"Not on Arcadia," Mattias answered, "Not even when our fortress world Reach was burning. Maybe, just maybe, a little when I had to kill all but _one_ of my squad mates because they got infected by a fucking basketball sized parasite, having to watch them mutate into something else, only for them to get back up again, this time trying to shoot me. The best part is that after you look into their face and pull the trigger, another fleshy basketball burrows into them and they get back up. So yeah, I'm the bastard who comes knocking when Death is too scared shitless do it himself!"

Mattias stopped yelling, suddenly aware that not only was Dr. Michel and Anderson looking at him, but Shepard and Ashley had entered when he had started his rant.

"I'm sorry to hear that Mattias," Shepard whispered, breaking the silence, "We had no idea, when did this happen?"

"It happened 6 months ago. I was attached to the Pillar of Autumn, part of _Operation Red Flag_," Mattias answered, angry that he had let his anger get the best of him, "But I don't want your sympathy, I did what I had to do to protect my squad. Hell I got infected first, I just didn't go down."

"Why didn't you go down?" Ashley now spoke, pain in her eyes.

"I didn't go down because some real classified crap was done to me, and I don't feel like sharing right now."

"Well don't worry," Ashley said, trying to comfort him, " The Citadel is the safest place in the galaxy,"

Before Mattias could say more, Dr. Michel came back with a AMTR VI which set to work on 'seeding' his chest with flesh.

"You think this place is safe?" Mattias said bitterness in his voice, "I've killed things, big things. And, believe _me_ when I say I can destroy this magnificent piece of scrap you call the 'Citadel'."

When Mattias had finished, the only sound in the room was the AMTR's humming. Shepard was however the first to speak.

"Mattias, I know you've been through a lot, but we could use your help"

"Help?" Mattias said somewhat resentfully, "You mean you need me to kill something. so far, all I've seen here is small, and easy to kill, you got it."

"Woah," Ashley said, surprised, "That's it?"

"Yeah, I've been bred for and shaped by combat. Not much good at anything else. Unless you count EOD work as something else."

_Post ARK Portal collapse, Location: In Orbit of Unknown Planet._

The phantom appeared in a flash of light, plasma fire billowing out the back, which a part had been sliced off by the portal collapse.

"Humans," The Elite piloting spoke, getting the attention of the four ODST's that were inside, "We must land on the planet, or else the antimatter core will detonate,"

"Do it," Jethro returned, grabbing what passed for a handrail, "Hang on guys."

_Eight hours later, back on the Normandy._

After the episode at the clinic, Mattias made sure that the tattoos he did have were in their proper place. Specifically the name and bar code on his upper left chest, and the list of 20 or so names, most of which were followed by a service number, that ran from his right collar-bone down to his waist, each one accompanied also by a date, and most had a location as well.

"Hey Shepard?" Mattias said once the decontamination sequence began, fake confusion in his voice, "Is there a reason Williams' took the shirt provided for me by the Doc.?"

"I'm not sure,"Shepard lied, giving a blushing Ashley a knowing look, "But I will have a word in private with her."

"Good," Mattias said, "If you will excuse me, I have something personal to attend to."

And with that, Mattias exited the airlock, leaving the two women alone.

"So, What do you think he meant by 'personal'?" Ashley spoke, not giving Jesse the chance to 'reprimand' her.

"I don't know," Jesse said, only slightly annoyed, "But you mind telling me why you were staring at a picture of Mattias on your omni tool?"

_Damn elevator,_ Mattias thought, humming the ODST hymn, _If Rico was here, he'd speed this thing right up._ Mattias' thoughts however, were interrupted when the elevator hissed open, and he saw Wrex teasing Garrus.

"Come on Garrus, where's that 'Turian Resolve' your race takes pride in?"

"Yeah Garrus," Mattias said, taking the opportunity to get some entertainment, "Scared because I can skin you alive with the toad's faceplate?"

Wrex just laughed as Garrus tried to busy himself with the Mako, more than a little intimidated. Mattias however, had ignored them and moved over to his pod, reopening his pod's emergency compartment.

"Hello beautiful," Mattias whispered, gazing at the contents, "Did you miss daddy?"

And with those words, Mattias took the set of armor within the pod and began to suit up.

"Wrex," Garrus finally said with annoyance, " If you don't mind, I'm still trying to get the Mako back in... To..."

Garrus trailed off when he saw a fully armored Mattias step out from behind the pod. Mattias helmet's blue stripe was barely existent, evidence that the paint had started to burn off the helmet, not to mention the many scratches covering the polarized visor. Along the top of the visor the words _Mors expectet nobis omnibus, _Latin for Death awaits us all.

The torso plate had pockmarks and slight plasma slag on it, nothing that would compromise protection. On the center of the torso an emblem of an alien skull with swords behind it (The Legendary difficulty emblem).

The arms were another story altogether, not only were they covered in gouges, but the gouges were highlighted by dried blood of various colors, which hadn't been cleaned out. On the left forearm, here was a knife that ran from his wrist to his elbow.

On his belt, there was a large pistol in a holster, as well as four clips sitting in pouches angled for a quick reload. That's without mentioning the many pouches that were for holding grenades and other magazines.

Then to top it all off, his right leg had the same knife that had nearly ended Garrus last time.

"Hey Garrus," Mattias said, grabbing the knife from his arm, twirling it in his fingers, "Does Turian taste good fried, or grilled?"

**A/N: Yup! Mattias is gonna be that loveable guy that does the stuff we want to do in mass effect, but can't, but don't worry, Mattias will find his answer, we'll just have to be patient.**

**NOW ATTENTION!: If any artists who appretiate my OC Mattias wish to, I could use a picture for the title, Either of him wounded early on, or in his 'new' armor, preferably stabbing something through the roof of it's mouth, actually, I don't care, Just something that looks epic, and I will be eternally grateful, as well as reference you in story. yes, that is incentivising, but I'm desperate (kinda) **

**Also, could use ideas for virmire, i.e. Who's gonna die, and if nobody, how do I get mattias to do the impossible? Because I have an idea, but it might by ****too**** ludicrous. **

**as always please read and review, more reviews=faster update **


	8. A Warm Up

**A/N: well i'm back with another dose of fresh fanfic. 5 reviews as of yet, good so far, **

**Themythick: I don't know, I got a hankering for somethin' deep fried, and it ain't chicken. **

**Still no word as of yet on willing artists, but It's only been a day, I'll give it time, I know it takes time to produce quality work, mainly because I spend atleast two days writing a chapter.**

**Mercenaries belongs to EA**

**Mass Effect belongs to Bioware**

**Halo belongs to 343 Industries**

As Shepard walked into the medbay, She had a lot on her mind. Mostly concerning Mattias.

"Hey Dr. Chalkwas," She said, gaining the attention of the CMO, "Is there anything unusual about Mattias, specifically his body."

"Well, accept for what he has asked be kept private," The woman answered, bringing up a file on a data pad, "Let's see... First is pulmonary respiratory enhancements, so he has the cardio and respiratory system of an olympic sprinter. Next there is evidence that he has had retina-inversion injections,which give him sharper eyesight and superior natural night vision. He also has cochlea enhancements, which allows for better hearing than normal. Finally, he appears to have neural augmentations as well, giving him an IQ of 156. Other than that. he has extensive wounds, several artificial ribs, likely due to excessive wounds."

"So wait," Shepard said, trying to comprehend what she had heard, "You're saying he is in better shape than anyone on this ship, smarter than anyone on this ship, and probably deadlier that anyone on this ship?"

"That's right Commander,"Chalkwas continued, "But the most interesting part is that his left arm is a cloned prosthetic, but he has a genetic mutation that would cause that type of procedure to suffer rejection syndrome. However, that same mutation seems to allow him to heal, almost like a krogan, but at a slower rate."

"What are you saying then?"

"I mean that even if he hadn't received treatment from a AMTR, he would have healed up probably within 5 to 6 weeks,"

_2 days later. Location: Feros, _

Mattias was sitting in his pod, surfing the extranet on the omnitool that Garrus had 'given' him when he expressed his interest in it. Currently he was comparing ballistics between his weapons and the Lancer I, pleased that they were relatively poor when it came to armor penetration, as well as kinetic energy transfer, only making up for it in fire-rate.

"_Garrus, and Kaiden report to the CIC,"_

"Hey Garrus, If you don't want to go, I could skin you and wear your skin like a costume, you know, as favor between us guys," At those words, Garrus hastened his pace, while Mattias and Wrex laughed.

"You know Mattias, I think I like you,"

"Hey now,"Mattias said, taking his helmet off, "Ashley there might get jealous"

"Hey!" the feminine voice protested, "That's uncalled for!"

"Yeah," Mattias continued with a devious smile, "So is calling me a hunk and giggling about me with your sisters,"

"_Mattias Nilson, Report to CIC"_

"Well" Mattias said, grabbing the MA5C stashed in the pod next to the seat, "Looks like my services are required"

"Good luck out there" Ashley said, overcoming her embarassment.

"Here," Mattias said, slipping a round out of a spare magazine, tossing it to Ashley, "Find a way to make more of these. Otherwise I'll end up snapping necks, and slitting throats."

After that Mattias turned around, heading towards the elevator, rifle at a relaxed, but ready position. Once the elevator finished its ascent Mattias walked up the stairs, annoyed at the design of the ship from a practical perspective. When he reached the top, he noticed Shepard talking with Kaiden, somewhat cheerfully, her back to him.

"So once the sergeant gets here, we're going to secure the colony."

"Yeah, but what do we need the sergeant for?" Kaiden asked, protectively.

"Yeah," Mattias said, interrupting, "Either you want me to do a slash 'n' burn, or do you want me to kill someone specific?"

"Niether," Shepard said, turning around, "I need you to be on standby, incase the geth push the survivors back to the Normandy,"

"Guard duty?" Mattias said, confused, "Guess I get to hang out with Mr. Limpy Limbs in the cockpit"

"Good, Kaiden, Lets go, Garrus is waiting in the airlock"

_A while later_

"Hey Joker," Mattias said, picking his rifle up from where it was propped against the bulkhead.

"What?"

"Check on external camera, I hear somethin' '"

Joker complied, the video feed showed a colonist banging on the airlock with the butt of an assault rifle, "Crap, You might want to take care of this, I'll try and reach the Commander."

"Already on it," Mattias answered, already beginning to cycle the airlock.

When the outer door of the airlock opened, Mattias didn't even hesitate, he just headbutted the hostile colonist, followed by a punch to the adam's apple, making him go to his knees.

"Buddy, we're gonna have a long talk about this when I'm not ordered to defend you." And with that, Mattias slammed the colonist's head into the Normandy's airlock door, knocking him out cold.

"Joker,"Mattias said, flicking the switch on his helmet's radio to _Transmit,_ " Any word from the commander?"

"_Yeah, Patching her through,"_

"_Mattias! Please tell me you haven't killed anyone yet."_

"No Ma'am" Mattias said, beginning to head towards the colony proper, "Subdued one hostile, preparing to investigate colony"

"_Negative, Do not engage. The colonists are being controlled by a creature, but we can break the control."_

Mattias stopped walking, his mind going blank, he then began to jog, checking his rifles ammo counter. "Will subdue the colony. Going silent," And with those words, Mattias flicked his radio to _Receive Only_.

Shepard was getting anxious, "I hope Mattias hasn't slaughtered everyone by now,"

"You seem awfully worried that he would kill everyone for fun," Kaiden said trying to calm her down as the elevator started to come to a stop, "I mean he doesn't even have barriers on his armor yet, he probably got killed himself,"

"I wouldn't underestimate him," Garrus said, more than a little terrified.

"Let's just get there," Shepard said, exiting the elevator, "No use debating it,"

As the team went down the elevator, there was an uneasy silence. However, that silence was soon explained: Rounding the corner to the colony, The colonists all lay in a line, all unconscious. The strange part was that a couple of them were missing an ear, Arcelia Silva Martinez however, was missing her ear, as well as the ring finger and pinky finger on her left hand.

"Uh Commander, This isn't what I thought he would do." Garrus said, slightly relieved before gunfire echoing in the distance caught their attention.

Mattias watched, surprised as the giant plant thing suspended before him began to birth a nude green asari.

"Hey lady" Mattias said, slightly angered, "Aren't you suppose to be blue?"

The asari before him began to stand, "We speak for the Old Growth,"

"Well," Mattias raised his rifle, "That's fine 'n' dandy, but, I have a proposition for you,"  
Mattias opened fire, letting out a four round burst, pulping the asari's head and shoulders. Mattias then grabbed his knife and jumped onto the house sized creature.

"How big is this thing anyway?"

"I don't know Garrus," Shepard said, running down the flight of stairs, "But we need to stop it, before it does any...more..damage"

Shepard was dumbstruck, She saw Mattias _climbing_ the Thorian, using his two combat knifes to help him scale the giant creature. When he reached what passed for it's eye, he cut a long gash in it, shoving a lunch box sized package into it.

Once Mattias had shoved the C12 demo charge into the creature, he continued to scale it until he reached the top. Once he he did so, he took out the detonator.

"In The Words of My Generation," Mattias hit the detonators lever, "UP. YOURS!"

A moment later, a loud bang pulped the lower half of the thorian, showering the squad in gore. Mattias had at this time leaped onto the upper level and began to make his way back down.

"What the Hell!" Kaiden shouted, wiping plant matter from his eyes.

Just then, Mattias came down the passage way on the right, with a slight limp in his left leg.

"Commander, Objective complete," Mattias said, coming to a halt, his rifle already back in his hands,

"Sergeant are you injured?" Shepard replied, concerned more for his safety rather than the mission.

"Nothing major," Mattias answered, slightly less formal now, "My knee pobably cracked when I landed, other than that, just bruises, Here,"

Mattias tossed a couple ears, and two fingers at Garrus, "Give those back to the girl in cheap armor,"

"May I ask why you have those?" Shepard said, slightly disgusted.

Mattias laughed before answering, "Yeah, they shot at me, I needed to take my pound of flesh out of them."

Before Shepard could answer him, Mattias quickly moved, pushing her behind him, his rifle snapped onto a clothed asari.

"Wait!"The asari said, putting her hands up, "I'm not an enemy."

Mattias leaned against the wall, listening to the asari Shiala give her explanation. His focus however, was on the asari's body language, scanning her over for traces of deceit.

"Mattias," Shepard said, pulling him from his thoughts, "You've been quiet, what do you think?"

"She's not lying," Mattias said, flicking the his rifle to semi auto, and firing a shot into the ground, causing everyone to jump, including the asari, "And if she was an assasin, she would have attacked just now, but it's not my call. I'm just a visitor _here_."

"Alright, enough for me," Shepard said, slightly surprised by his ability to judge people, "Give me the cipher,"

Mattias took this as his opportunity to head back to the Normandy, heading back up the stairs. As he went, he noticed that some of the colonists had started to wake, but only Fai Dan was fully concious, with a dislocated shoulder.

"Hey man," Mattias said, walking up to him, " good to see your awake,"

"Yeah," Fai Dan grunted, as Mattias popped the shoulder back into it's socket, "Thanks for saving Zhu's Hope"

"Yeah, those with missing ears might disagree," Mattias said, leaving the leader wondering about the metaphor.

When Mattias reached the Normandy's airlock, he gave the previously aggressive colonist, a smack on the head, snapping him to consciousness.

"Buddy, If you ever get mind controlled again, You're on your own."

_Location: Unknown planet_

As his vision began to clear, Jethro moved an unconcious Mikey off of him. Looking around the phantom, he noticed that Echo squad, or what was left of it, was thrown to one side, probably due to the crash. The blue interior was only dimly lit by a few pulsing lights, in the cockpit, the Elite was dead, cooked alive by an overload of several systems.

Jethro swore, then pushing a button that he had seen the elite push when they first entered the phantom, one of the ramps in the troop bay lowered, showing a snowy landscape. "Guys, We have a problem."

Mattias was leaning against the wall in the briefing room, listening to the various crew members. He did however notice when Liara did the 'Embrace Eternity' thing.

"The message is clearer," Liara said, looking slightly wobbly, "But it is still incomplete,"

"Alright," Shepard said, "Everyone but Mattias is dismissed,"

Mattias pushed himself off the wall, knowing full well that his still gore covered armor intimidated everyone, save Wrex. He moved closer to Shepard, opting to depolarize his visor, rather than take off his helmet.

"Need something Commander?" Mattias asked, curiosity peaked " Because I was thinking of having a 'Chat' with Jenkins."

"You," Shepard began, not wanting to know what this 'chat' was about, continued, "Are going to stay here and explain to the Council what it was you did,"

"Commander," Mattias began, repolarizing his visor, "You're gonna learn real fast, that when I deal with politicians, I solve a _**lot**_ of problems, and occasionally create them. So you can tell them that I said "Fuck You" with brick of plastic explosive."

Just then The Comm feed went live, showing a hologram of each of the councilors. Of the three, Tevos was obviously the least surprised by his presence, however, all were taken aback by the coat of gore over his armor, including Sparatas

"Commander," Valern, the Salarian councilor began, "We received your report. What was this Thorian creature?"

"Councilor, it was a creature that released spores," Shepard explained, "These spores, however, attacked the nervous system, giving the Thorian control through pain conditioning,"

Mattias gave a nostalgic laugh at that last part, which raised additional questions.

Sparatas now spoke, "Your report also states that this Master Gunnery Sergeant Nilson disobeyed orders, successfully subdued the whole colony, and then took out this creature when it tried to communicate with him, and yet, here he is, unrestrained. Please enlighten us Commander."

"You know what, I don't like you," Mattias said, before Shepard could defend him, "First,I've read the Commander's service record. I have more expirience dealing with this type of situation. Second, I would have killed everyone in that colony who appeared hostile, let alone subdue alive. I didn't however, because I was informed that they were being controlled." Mattias stopped anger starting to enter his voice, "Third: The Thorian committed hostile action first, therefor, no reason not to kill. Fourth, you're a jackass. Fifth, If I EVER see you in person, I will leave you something to remember me by." Mattias said that last part with his hand gripping his knife, "And finally, I'm not restrained because if anyone so much as tried to do so, Everyone on this ship is as good as dead."

Sparatas looked slightly taken aback. _Good,_ Shepard thought, _but that is a little disconcerting._

The Turian councilor continued however, "Making threats to the council isn't a wise idea _human_"

Turning to leave, Mattias had one thing to say to that, "Never been one for threats, you'll find that out. Hell, I might just skin you alive with your own _teeth_. You know, mix things up."

Mattias walked out of the comm. room, heading straight for the hangar. Reaching the elevator, he punched the button. When the elevator came to a stop, Mattias walked right over to where Ashley was fiddling with what looked like a 3D printer.

"Ashley," Mattias said, slightly startling her, "You make me more ammo yet?"

"Sorta," The marine said, scanning the bullet again, "I can make the bullets and cartridges, but propellant is something else though,"

"If you need sulfur," Mattias said in a condescending tone, walking towards his pod, "Get it. How, I don't care. Distill it from onions if you have to. And yes, onions due have a lot of sulfur."

Once Mattias reached his pod, he stowed his rifle, then removed the armor surrounding his knee. _I'm getting too old for this._ Once the his swollen knee was visible, he grabbed the first aid kit that was in his pod, grabbing a compression bandage. Once the bandage was wrapped, Mattias took out a rag, along with a tooth-brush, and began to clean his armor.

After about ten minutes of cleaning, Mattias noticed Shepard sitting on a crate, watching him.

"What do you need Commander?" Mattias said, placing the shin guard back on his armor.

"Just looking for personal input," Jesse said, crossing her arms, "Like why you disobeyed me, and said that I didn't know how to handle the situation on Feros,"

Mattias now took out his knives, placing them on the arm rest of the pod's seat, "I said you weren't as experienced as me. Not that you didn't know how to."

"Please," Jesse said, standing up, "Tell me the difference"

"How many times have you taken down armed women and children?" Mattias asked not waiting for an answer, continued, "None. Did you know that I've had to kill child soldiers? And that most of those kids are so drugged up that they couldn't tell you why they're shooting at you?"

"Mattias," Jesse said in a gentler tone, "I had no idea. Is there a way I can help?"

"Yeah," Mattias looked up, "Send me back,"

**A/N: yeah, This chapter was starting to run long, so, this seems like a good place to stop, but don't worry, I'm already working on the next chapter, Learned a bit about Mattias, and for those of you who have guessed already, you're probably right, because I've been leading up to this since I first came up with Mattias. For those of you who don't know, stay tuned.**

**Now, I would like to have someone who also writes MExHalo Crossovers, to message me, and let me use you for an idea board. **

**Also: Once I have developed decent (I Judge myself very critically,) Writing skills, I will do a rewrite, for now though, we go onward,**

**FYI: Still no word on a piece of art for a cover, I will accept multiple's and the one I accept will be the Cover, with bragging rights and everything for the artist.**

**Read and Review. more reviews means more awesomeness **


	9. Love's Lost

**A/N: THIS IS A DOUBLE UPDATE, SO IF YOU HAVEN'T READ THE PREVIOUS CHAPTER, PLEASE DO SO**

**Sabre Knight: Thank you for accepting another dead elite. I actually had ideas for him, but, since this is my first fanfic, or even piece of writing I have ever done that's not related to school, I chose not to have too many characters I need to make up. Also, I wasn't sure how he would fit into mass effect, Mostly I didn't want to come up with a name, or write his dialog. Besides, and elite with plasma weapons and energy shields would be overpowered in the mass effect universe.**

**Mass effect belongs to bioware,**

**Halo belongs to 343 Industries**

**Mercenaries belongs to EA (Still angry that they shut down the online servers for mercs 2, don't know what they're doing over there)**

"Wait," Shepard said in disbelief, "You want to go back there? You make it sound like it's filled with nothing but death."

"It pretty much is," Mattias said, returning to sharpening his knives, "But my orders still stand, give support to Sierra 1-1-7. There's also people there that need me."

"All right Sergeant, That will be all."

"By the way," Mattias said, not looking up, " Where are we going next?"

"A planet called Virmire," Shepard informed, "Our target is a Turian named Saren, He's trying to bring back the Reapers, a race that's wiped out life in the galaxy dozen's of times."

"Good," Mattias said, sounding happier, "This place is starting to feel like home."

As Shepard turned to leave, she suddenly stopped, " Mattias, before I forget, go see Tali. She's going to install a barrier on your armor."

"I'll consider it," Mattias said hesitantly, putting his knives back in their proper sheaths.

Once the commander had left, Mattias took out the datapad that was stored in a hard case on his belt. He then took out a cord and plugged one end into his helmet, then the other into the data pad. However, his helmet only had about ten minutes of footage, then cut out. _Crap, out of memory, but what's taking up the rest of the helmet's data?"_

Mattias tapped the screen, going back to check the timestamp:_ 20, September, 2552_. By now, Ashley had walked over, holding two bullets, a triumphant look on her face.

"Done, Now you can go trigger happy," Ashley said, tossing it to Mattias, who caught it, "What are you looking at?"

"My armor has some old footage on it," Mattias said, rapping the datapad against his knee, "So unless you want to not sleep for a week, I suggest you leave it at that."

"Please," The marine said, "I've fought cybernetic zombies, I can handle it,"

"Yeah?" Mattias said, "Face it, the only difference between you and Jenkins is combat experience. You're not a killers."

"Oh!" Ashley exclaimed, her voice getting louder as she spoke, "And You are? So far, all you've made are threats, and..."

Ashley trailed off when she noticed Mattias looking behind her, taking his helmet off. She turned around seeing Shepard being trailed by Tali, both probably investigating the source of the yelling.

"Ashley," Shepard said, taking long strides towards her, "What are you doing?"

Ashley came to attention, snapping to attention, "Ma'am I was trying to persuade Mattias into sharing a video."

"And Gunnery Sergeant," Shepard said, turning to Mattias, "What is the nature of this video?"

"Combat footage," Mattias said, slightly nervous about having to comply with Ashley's desire to watch the video.

"Well, "Shepard said, Tali who had come closer, also seemed curious, "Why don't you share it with us,"

"Fine," Mattias said, tapping his datapad, "But I did warn you. And Ashley, I better get an apology card from you."

_Location: Unidentified Ring World_

_IFF: Master Gunnery Sergeant Mattias Nilson _

Mattias moved through the dark swamp in knee-deep water. Behind him in a delta formation was his squad, Jethro, Martinez, Pat, and in the rear was Carson. All were equipped with an Assault rifle.

"Yo Sarge, What are we looking for?"

"Martinez," Mattias said to the spanish accented marine to his right, "You heard Keyes. We're to scout the swamp for covenant while he, Alpha, Bravo, Charlie and Delta secure the weapons cash,"

"How?" Jethro said, somewhat nervously, "I mean, it's pitch black out here,"

"Jethro, you might be close to Nat," Mattias light-heartedly scolded him, "But that doesn't mean that you get special treatment. Besides, We have motion trackers, they have glowing weapons. Shoot anything that looks like a firefly, and don't split up."

"Uh, guys," Carson finally spoke up, quickly turning around, "My motion tracker, it's malfunctioning,"

Mattias glanced at his own in the bottom left of his visor, "No It's not! ECHO, circle up!, Martinez, pop a flare, NOW!"

It was then that Mattias felt something land on his back, then scurrying up and latching on his shoulder. Incredible pain filled his body, before a chemical cocktail numbed him. By now, more of the things had fallen from the trees landing around the squad, causing splashes all around them. After about four seconds, Mattias recovered enough to pull thing of his neck, revealing a long tendril that had blood covering the length of it, and threw it at a tree, "ECHO, Out Of The Water!"

By now, the squad had recovered enough to open fire, however, Carson was attacked, going down somewhere beneath the water, while pat had panicked when Carson went down and had run off, shooting at anything that moved, Jethro and Martinez however managed to acknowledge the order, moving to a mound of dirt that poked out of the water. As Martinez scrambled up the ledge, something grabbed his ankle, pulling him down causing Jethro to fire into the water, behind where Martinez had been, stopping only when the bubbles ceased."

Mattias and Jethro stood on the small hill, silence except for the sudden scream from Pat, probably only a 100 meters away. Mattias grabbed a red flare, lighting it then setting it down on ground, checking his ammo indicator.

"Jethro," Mattias said, noticing how the soldier was sitting on the ground, both hands on his helmet, shaking, "Keep focused, We need to leave, now."

"Sarge," Jethro's voice was shaking slightly, "I don't want to die here,"

"Neither do I," Mattias answered scanning the water, assault rifle ready, "But right now, we can't be afraid to die here. Those things, they do something, one of them bit me, kind of like a mosquito,"

Just then, a low moan could be heard as Carson, or what was left of him, rose from the water skin tone different, and there were poking out of his chest cavity, which appeared to have been borrowed into. His left arm had morphed into a kind of claw, while his right clutched his assault rifle. His face had a blank expression, except for his eyes, which glanced back and forth.

"Carson?" Jethro asked, walking towards him, "Are you OK? Carson?"

Mattias stopped Jethro from moving any closer by putting his left hand to block him from going closer. Mattias however was now aiming his rifle at Carson one handed, "Jethro, that's not Carson,"

"Yes it is!" Jethro said, grabbing some biofoam from his first aid kit, "Carson, get over here,"

Before Jethro could move closer, Mattias pushed Jethro to the ground, right before the creature that had been Carson jumped at them, screeching. The moment it jumped however, Mattias opened fire, but it took about half of his clip to take it down.

"Jethro," Mattias said, taking out a grenade, "Next time I say something, don't argue with me. If you can't do it, I'll put down Pat and Martinez should they end up like Carson."

"Okay, I, I understand," Jethro said, obviously scared,

Mattias pushed the detonator button on the grenade, tossing it into the water, "Come on, I think we're on the menu tonight."

Mattias paused the video, mostly because he could tell that his audience had seen enough. Both Ashley and Shepard had to look away several times, and both looked sick. Tali however, had obviously muted her helmet during parts, and looked very spooked.

"There, now you know about the _Flood_," Mattias said, angrily, "Happy now?"

"Mattias," Shepard said sadly, "I had no idea,"

"Yeah," Ashley agreed, "I'm sorry"

"H-How did you make it out of there?," Tali, who had recovered a little, now in awe of the violent man before her.

"What do you mean?" Mattias asked, sounding like this type of situation was normal, "I killed, just like I'm trained."

"No," Tali said, not getting the answer she was looking for, "I meant, why didn't you _change_?"

"Oh," Mattias replied, seemingly more forthcoming when questioned by Tali, "Well, I have this condition called 'Borens Syndrome'. The ONI 'Doctor' said that it kept the Flood from fully interfacing and taking control of the nervous system. Hurt's like hell though."

"How did you get Borons?" Shepard asked, connecting the dots.

"Officially," Mattias said, his cold tone returning, "I got hit in the helmet with a plasma grenade-which did happen on New Jericho - and by the time I got rid of the helmet, the radiation scrambled the neurons in my brain. I then had to get treatment for a brain tumor."

"Wait," Ashley asked disbelievingly, " You had brain cancer?"

"What?" Mattias said, looking at her like she just licked a bug covered windshield, "I said that was the official story, not the same as the truth."

"So what did happen?" The quarian asked, her eyes wide in shock.

"Well," Mattias said, thinking for a moment, _What the hell, Spartan II's are public knowledge, besides, it's not like it could hurt anything_, "Well back in the 2300's, the UNSC had an idea: Let's make supersoldiers, that was Project: ORION. It was soon abandoned, but, about a hundred and fifty years later, it was adopted."

"What's this have to do with any of this?" Ashley said, getting impatient.

"Well, If you had patience," Mattias said giving her a look that could freeze beer, "I'd tell you. Anyway, ORION soldiers were all volunteers, given all types of enhancements, from better eyesight, to improved mental abilities. I just so happen to be an ORION soldier. Which means you are looking at the UNSC's first generation of super soldiers."

"Wow," Tali said, beginning to get bubbly, "What were the other generations?"

"All I know of are the Spartan II's and III's," Mattias said, less informed on the subject, "But, if you really want to know, Spartan II's really are super soldiers, ten times faster than the normal human, Ceramic coated bones, have natural night vision, 7 foot tall. I've met two. First was David-143, He got wounded to bad for active duty, met him on a hospital ship, Great guy, shattered my shoulder arm wrestling, thing is, he was a prankster, we once set my vital's to show I that my lungs collapsed. The look on that nurses face when I kissed her when she started CPR, priceless."

"That's horrible," Shepard said, holding back laughter.

"Not really," Mattias returned, stopping his said laughter, "That turned out to be my future wife. Anyway, the other spartan II I've met was a Master chief 117. Not a talkative one, but he was lethal, hell, He probably would have evaced us if our radios hadn't stopped working.

"This the same 117 you keep referring to?" Ashley asked.

"Yeah, Anyway, Spartan III's, " Mattias said, getting slightly angry, "They were ONI's answer to the cost problem of Spartan II's, Disposable Shock Troops. They were still superior in every way, including power armor. But ONI trained them from 6-8 year old war orphans, Sending them into combat at age 12. I met a few, most notable however, was Emile, mean bastard, had a skull carved into his helmet. Think of him like me, but bigger, deadlier, meaner, and better at poker."

"Wait, what about poker?" Tali said, still shocked at the child soldier part.

"I played him once," Mattias said, getting angry, "I use to have this nice, beautiful machete. But the bastard cheated, I know he did."

**A/N: well, yup, I be back, mainly because there was nothing to due, and I don't want to keep my small, yet growing and loyal fanbase waiting, plus MORE AWESOMENESS**

**Also, That's right, I went there Emile, That glorious Kukri belongs to Mattias, and face it, YOU COUNTED CARDS**

**anyway, up next, probably some character building, leading into Virmire, also, I'm starting to make Mattias more...Mattias-y**


	10. Six pedals?

**A/N: Well, I'm back, yet again. before I rant, some reviews:**

**Leonard Church814: No, It's not Kukiri, It's Kukri. I know because I have a Cold Steel Kukri. FYI, don't purchase it through their website, because when I did, they messed up the order and sent me a F***ing ROMAN GLADIAS! I kid you not, it's too outraguose even for me to make up, so I sent it back, got my refund, and ordered the same knife through Cabela's, said it was supposed to take 6 days to ship, arrived at my house in 3, also, an actual Kukri is a sword and a good 8 inches longer than the one Emile has, which is the machete style that you can buy at a sporting goods store.**

**Now, BIG shoutout to to ZeroStealth 117: That review is so far my favorite. When I created Mattias halfway through chapter 1, I had in mind the OC's from Halo that in front of the council, they're all nice and respectful, while in their head, they just want to punch someone, specifically the turian councilor, and Udina. Which by the way I've seen Udina get a verbal smack down, I think it was about time to give him the physical one.**

**themythick: Thanks for the clarification, honestly, I couldn't remember so I just came up with a reasonable number, using the number of infected flood forms I remember encountering as a guideline. And yeah, you've reached that conclusion on your own, but bear with me, because if you know how old Sergeant Johnson is, you might know how Mattias is going to handle this.**

**Anyway, on with the show:**

**Mass Effect belongs to BioWare**

**Mercenaries belongs to EA**

**Halo belongs to 343 Industries.**

It had been about an hour since Mattias had shown everyone else the kind of hell he had been through, or at least part of it. He was resting his elbow on his knee, propping his head up while his other hand unconsciously touched the back of his neck, feeling the ridges of the scar there.

While he was sitting there, he failed to notice Tali, carrying with her a tray of food. After about a minute, she spoke up. "Mattias, I brought you some food, are you okay?"

"No," Mattias said softly, looking up, his eyes softening, "No, I'm not."

Tali put the tray of food down on a crate next to Mattias' pod. "Do you want to talk about it?"

Mattias gave her a soft smile, "No. But If you want to talk about something different, sure."

"Sure," Tali said changing the topic, "But the Commander wants me to hook up a barrier to your armor,"

"Well," Mattias said, undoing some seals on his torso armor, "While we do that, I have a rifle to clean."

_0400 hours, the next day (Same system as Virmire)_

_"30 seconds to impact, standby"_

Mattias glanced at the decreasing altitude displayed in the top corner of his HUD, then looked back out to the rapidly approaching surface of Harvest. In the background, dozens, if not hundreds of flaming streaks approached, beginning to form clusters. The whole battle cluster's deploying. This is big.

_"Incoming! Evasive maneuvers"_

Blue and green streaks had begun to fling up at the clusters of pods. One streak zipped by, taking out the command pod of Delta squad, with dozens more filling the air around him.

_"WE ARE SO FUCKED!"_

"Can it Patterson," Mattias said, checking the readout from the class C 'Dumb' AI in his drop pod, "ECHO, 10 seconds"

Mattias grabbed the joysticks on the arm rests of the crash chair, manoeuvering the drop pod out of the killzone of another barrage of plasma, sending it through the roof of a grain silo, the force of impact spreading the grain that was within.

Mattias snapped awake, the slight vibration of the Normandy exiting FTL reminding him where he was.

"Definitely not Harvest," Mattias said, sitting up from the cot set up next to his pod. Looking around, he remembered where exactly he was, fighting someone else's fight. But before he could stand up, the elevator door opened, revealing Shepard with Tali.

"So," Shepard whispered, nodding towards Mattias, sitting on his cot, elbows on his knees, head in his hair, "What do you think about Mattias?"

"Well, he's interesting," Tali whispered back, scratching the back of her hand, "He's very protective about something, but he prefers to listen, not talk."

"Yeah that's right," Mattias shouted standing up, revealing his heavily burned T-shirt that had been crudely patched, "Doesn't mean I don't like to talk."

"Mattias," Shepard called out, "Get ready, You're driving"

"What, the tank?" Mattias said, strapping on his armor, "Been a while since I've driven one."

"Yeah," Shepard said, "You drive, I'll gun."

Location: Uncharted planet,

Jethro looked up out of the ice cave they had carved out using the elite's energy sword to melt it, Well, hope we find something native. "Hey Mikey, where's Shiner?"

"Outside," Mikey said, looking up from the pile of MREs and assorted equipment, "Their fortifying the entrance,"

"Alright," Jethro said, putting his helmet on. "And Mikey, We may need to count that Elite as food, along with the cryo crap,"

"Fine," Mikey answered, "But I vote we eat Shiner before we all drink that crap."

"Agreed," Jethro replied, although he knew Mikey wasn't kidding, "But we start with fingers, something he can function without."

Location: Virmire surface

As Mattias swapped positions with Shepard, he felt an odd sense of nostalgia at the controls of the Mako,. The interior was cramped, but the interface seemed to be a hybridization of a Scorpion, and a Warthog.

"Mattias, Do you need a run through of controls?"

Mattias slid his helmet off smiling, "I think I'll manage Shepard," with that, he hit the throttle heading upstream of the river they had landed in.

"Hey Shepard," Tali said after a couple of minutes passed, "Mattias should drive more often. This is actually nice."

"What are you saying?" Shepard light-heartedly answered, "You don't like me driving?"

"I'm saying," Tali returned, "That I could have eaten a larger breakfast."

Mattias tuned them out, opting to keep focused on driving. Glancing down at the radar however, he spoke up. "Contact, 50 meters out. Bearing at 11 and 2 O'clock."

"Drones" Shepard said, whittling the barriers down with the co-axial machine gun, followed by a round from the main cannon, obliterating the drone. Without waiting, Shepard rotated the cannon taking out the other drone with the machine gun, destroying it before the cannon had finished cycling.

"Targets neutralized," Mattias said, checking the radar. "Proceeding to first objective."

The rest of the way down the river was uneventful, the only contacts being the occasional pair of drones, with a squad or two of ground troops. Having reached the first gate, Mattias exited the Mako, firing his assault rifle in bursts. The MA5B easily dispatched Geth troops, and while it's rounds where much slower, they were also much, much heavier, making it difficult to deflect.

The only real trouble encountered was the Geth Destroyer, which went down under the combined fire of Shepard, Tali, and Mattias. Once the Gate and antiair turret were down, they returned to the Mako. They repeated this cycle several times, which while encountering a colossus, Mattias rammed it, using the Mako's weight to help grind its head to scrap.

Mattias climbed out of the lower Mako's hatch, he felt the humidity hit him like a wall, the smell of ocean flooding his nose.

"Mattias, Tali," Shepard said, climbing out of the Mako, turning towards the camp, "Try and help out around the camp. I'm going to check in with the STG Captain."

"Alright Commander," Tali said, getting out of the Mako and into the knee-deep water, "Hey Mattias, how come I'm miserable in an enviro suit, but you're wearing heavy armor?"

Mattias gave a quick chuckle before replying, "Two reasons. A, I've been on a planet similar to this one. And B, I am miserable, but complaining won't do anyone any good."

"What planet was that?" Tali said, thinking of planets she'd heard about.

"Arcadia," Mattias said, heading towards one shelter that looked like a comm. center. "Twice, Once in the jungle, chasing terrorists. Another time evacuating the colony, just about died both times."

"So this is normal for you?" Tali said, looking up at the soldier, somewhat intimidated, and in awe.

"What, jungle warfare? Or Dropping into combat at terminal velocity inside a self burying coffin on some backwater planet that you'll probably die in?" Mattias said, taking his helmet off, setting it on a table in the shelter. "Because the answer is yes."

Meanwhile, with the rest of ECHO,

"Hey Jethro!"

"What?" Jethro called, turning towards the entrance of their cave.

"Dinner is on me!" Rico called, coming down into the cave, bathed in the light of the plasma coils they had set up. In his right hand, a bloody boot knife. But in his left hand, dangling by the tails, where what looked like half a dozen decapitated monkey's. " Looks like Shiner get's to live."

"HEY!"

"Shut up Shiner," Jethro said, trying to calm him down, " He's kidding,"

"My stomach wasn't," Mikey growled, " At least Jimmy was worth his weight in rations.,"

"Yeah, but he was visiting his family in New Mombasa," Jethro said, taking his helmet off and looking at his reflection, " Last I heard, He was fighting the damn flood before the elites came in."

**A/N: Sorry for the delay, my brother's computer, which is my prefered method of writing has been removed from my grasp temporarily, so updates will be slower.**

**also some epic referencing to a fic that I can neither confirm nor deny that I'm writing, but will have some sort of an impact in this one. so hope you enjoy. Yes I skipped over most of the Mako trip, but hey, we all know how it goes, if you don't buy mass effect you dirty hippy.**

**I now have a character reference sheet, and am looking for an idea soundboard I can bounce ideas off of, as well as get some input from regularly.**

**Still looking for an artist to possibly get me a cover photo of ECHO squad.**

**Please review, because if I don't get input, this story will get lame, and those who've read this far probably wouldn't want that.**


	11. Chapter 11

**This story is having a rewrite, and Chapter one is posted under "Through the Gates of Hell (Rewrite)"**


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